1. Field of the Invention
This application relates to an instrument for applying surgical clips to body tissue, and more particularly to instruments for applying surgical clips for anastomoses of a blood vessel in conventional surgical procedures and in endoscopic or laparoscopic surgical procedures.
2. Discussion of the Prior Art
The term "anastomosis" covers a variety of procedures in which blood vessels such as veins and arteries, or other tubular members, such as parts of the colon, intestines, stomach, etc., are joined or reconnected. These vessels may be joined in a variety of relative orientations, including end-to-end and end-to-side. Solid tubular structures such as peripheral nerves can also be joined together, as well as solid structures such as subcutaneous tissue and skin.
The recent advances made in the field of microsurgery has led to the development of alternatives to conventional suturing processes of joining vessels in order to accommodate the minute size of the vessels, nerves and tissues being joined during microsurgical procedures. These alternatives have also been developed with an eye towards preventing thrombosis which tends to occur at the points of penetration of the needle and sutures.
An alternative to suturing is the use of surgical clips which are applied along the juncture between the vessels or tissue portions which are to be joined, and the clips perform a holding function similar to that of sutures, but without penetrating the vessel walls or the surface of the tissue portions. Two such non-penetrating clips are shown in U.S. Pat. Nos. 4,586,503 and 4,733,664 to Kirsch et al. The former patent discloses a surgical microclip formed of plastically deformable metal or plastic material having minimal springback when crimped. The clip has a pair of parallel curved legs joined by a bridge at one end and terminating in rounded tips at the other end. The clip grips the edges of adjacent and everted tissue by crimping the legs together. The latter patent discloses a vascular surgical clip comprising a plastically deformable body portion, a tang for deforming the body, and a neck connecting the tang to the body. The body is designed to deform upon application to the tang of a predetermined tensile force, and the neck is designed to break upon application of a force in excess of the predetermined force to the tang.
As described in the above patents, the non-penetrating clips are applied over opposed edges of the vessels, the edges first being everted, or turned outward, to form flanges that are gripped between the jaws of the clips. Eversion not only enables the clip jaws to better grip the vessels, but also insures that only the interior surfaces of the vessels are in contact.
Vascular microsurgical clips are typically applied with a small hand-held tool that enables the surgeon to precisely place the clip over the tissue edges, and then to close the clip, as by applying a squeezing pressure to the tool. One example of a prior art clip applier for use in vascular microsurgery is disclosed in both U.S. Pat. Nos. 4,733,664 and 4,929,240 to Kirsch et al. These patents disclose a tool for applying a surgical clip, the tool including means for gripping and applying tension to the tang of the clip while also having means for simultaneously pushing against shoulders on the clip body. The tool disclosed in these patents requires that a clip be reloaded into the clip applier after each clip is fired, which is disadvantageous in that the vessels being repaired need to be returned to their intended function as quickly as possible, particularly blood vessels.
The need therefore exists for an instrument for applying such a surgical clip which can be utilized for vascular anastomosis. One specific need is for an instrument that can hold a plurality of clips and automatically feed and apply the clips individually to the vessel. It would be beneficial for the instrument to permit operation at various orientations with respect to the longitudinal axis of the instrument, such as through the provision of a rotation knob to rotate the body portion of the instrument. The instrument needs to be simple to manufacture, easy to manipulate and capable of applying clips with consistent accuracy so as to provide a secure joining of vessels and tissue. Since the instrument is intended to apply clips during vascular anastomosis it would be desirable to configure it similarly to other vascular surgical devices, i.e. tweezers or pincer-like implements, which are held between the thumb and forefinger of the user.